<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script type="text/javascript">
    var animal=new Array('dog','pig','cat','duck');
    animal['guangxi']="monkey";
    animal.north="wolf";
    animal[4]="tiger";
    animal[20]="panda";
//    for(var i in animal){
//        console.log(animal[i]);
//    }
//    var obj={
//        a:'1',
//        b:2
//    };
//    for (var k in obj){
//        console.log(k);
//    }


</script>
</body>
</html>